ICD-10 N12
Billable / Specific CCTubulo-interstitial nephritis, not specified as acute or chronic
About ICD-10-CM N12
ICD-10-CM code N12 represents Tubulo-interstitial nephritis, not specified as acute or chronic. This is a billable/specific code in the Genitourinary System chapter (block N12). The 2026 edition of ICD-10-CM N12 became effective on October 1, 2025.
Coding Tips for N12
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
N12 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under N12. Per CMS ICD-10-CM Tabular 2026.
- Interstitial nephritis NOS
- Pyelitis NOS
- Pyelonephritis NOS
Type 1 Excludes
Pure excludes, these codes can never be coded together with N12. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- calculous pyelonephritis (N20.9)
Inpatient DRG Impact, CC
1328:228 codes Tubulo-interstitial nephritis, not specified as acute or chronic. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for N12
Local Coverage Determinations (LCDs) from CMS MACs that list N12 as a covered diagnosis.
Showing top 10 of 12 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing N12.
2 Medicare
CPT Codes Commonly Billed with N12
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Convert N12 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| N12 | 59080 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To N12
Other codes in section N10-N16 (Renal tubulo-interstitial diseases).
ICD-10 N12, Billing FAQ
Is ICD-10 code N12 billable? +
Yes, N12 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to N12? +
ICD-10 N12 includes: Interstitial nephritis NOS; Pyelitis NOS; Pyelonephritis NOS.
What codes are Type 1 Excludes for N12? +
Type 1 Excludes (never code together with N12): calculous pyelonephritis (N20.9)
Is N12 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What ICD-9 codes does N12 map to? +
Per CMS GEMs, N12 maps to ICD-9 codes: 59080. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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